Self-regulating continuous-current dynamo



A. H. MIDGLEY.

sm REGULATING commuous CURRENT DYNAMO.

4 7 APPLICATION FILED DEC-21,1918- 1,419,071. PatentedJune 6, 1922.

2 SHEETSSHEET llNV F. NTOR I9. 1 Mi/d/ hy. m zmwk,

ATTQRNEY A. H. MIDGLEY. SELF REGULATING corxmmuous CURRENT DYNAMO.APPLICATION FILED DEC.2I, 191B.

1 ,41 9,071 Patented June 6, 1922.

2 SHEETS-SHEET 2- INVENTOR BY g0? ATTORNEY UNITED STATES PATENT OFFICE.

ALBERT HENRY MIDG-LEY, OF ACTON VALE, ENGLAND, ASSIGNOR 0F ONE-HALF TOC. A. VANDERVELL & COMPANY LIMITED, OF ACTON VALE, ENGLAND.

SELF-REGULATING CONlINUOUS-CUBRENT DYNAMO.

Application filed December 21, 1918.

1 '0 all whom it may concern Be it known that I, ALBERT HENRY MIDG- LEY,a subject of the King of Great Britain and Ireland, and residing atlVarple Way, Acton Vale, in the county of Middlesex, England, haveinvented certain new and useful Improvements in and Relating to Self-Regulating Continuous-Current Dynamos, of which the following is aspecification.

This invention relates to an improved variable speed self-regulatingcontinuous current dynamo.

The main object of the invention is to pro vide a method ofself-regulation which shall be especially useful in connection withvariable speed dynamos of small dimensions.

It has previously been proposed in connection with variable speedself-regulating continuous current dynamos to short-circuit a pluralityof armature conductors by means of a single wide brush, or two brushes,con nected together directly, or through the intermediary of anadjustable resistance, which short-circuited conductors were arranged inthe armature cross-field acting in conjunction with auxiliary poles. Theob ject of this arrangement was to provide a deniagnetizing flux actingin opposition to the main flux of the machine so as to produce aconstant current independent of the varia tion in speed of the dynamo.

According to the present invention the de magnetizing field acting inopposition to the main field for producing a constant currentindependent of the speed variations of the dynamo, is produced by ashort-circuited current flowing through the armature conductors lying inthe fringe of the main poles, viz, under the lagging pole tips withrespect to the direction of rotation of the machine, that is to say, itis not produced by a cross flux but by the main flux itself, so that theauxiliary poles are entirely dispensed with.

Specification of Iietters Patent.

Patented June 6, 1922. Serial No. 267,821.

Figures 1, 2 and 3 in the accompanying drawings illustratediagrammatically and, by way of example, three diiferent modes ofcarrying the invention into effect.

Referring to the arrangement illustrated in Figure 1, the two widebrushes, or the two pairs of brushes a a and a a, connected together bya short-circuiting conductor 6, b, are arranged to short-circuit thearmature conductors 0, 0 respectively, which lie in the fringe of thepoles S where the density of the magnetic flux is a maximum, the currentflowing through these short-circuited armature conductors producing ademagnetizing field A acting in opposition to the main field. Each ofthe pairs of brushes a a and a a may be replaced by a single wide brush.

According to the arrangements illustrated in Figures2 and 3, the mainbrushes B B of the machine are arranged in a neutral position, and inaddition thereto use is made either of two auxiliary wide brushes a, a,(Fig. 2), or of two pairs of short-circuited brushes a (Fig. 3),arranged underneath the backward edge N S of the poles N S.

It will thus be seen that'in the arrangement according to the presentinvention, the wide brushes, or their equivalent, are shifted back, ascompared with the usual shifting forward of the brushes for ensuringsparkless commutation.

The invention is applicable, not only to bipolar, but also'tomulti-polar machines.

What I claim is z--- A variable speed self-regulating continuous currentdynamo having an armature and armature conductors thereon, main poles,and means for short-eircuiting a plurality of armature conductors lyingunder the lagging pole tips, as set forth.

In testimony whereof I have signed my name to this s ecification.

ALBE T HENRY MIDGLEY.

